Things I liked:
-Opening narrations: Tenzin's first narration made me fangasm first time I heard it. I also adored the later narrations, specifically the brown and lighter brown opening narrations. They give off a great old-timey feel, especially with the awesome narrator's 1920s radio drama-esque rapid line reading. Great for the setting, really puts you into the mood. I also liked Tarrlok's recap(even though it was just his lines from previous episode), due to how lines are rearranged to seem like a political campaign speech.
The setting:While I am not sure if I want to see only Republic City for rest of the seasons(or rather, books), for the first book, it is absolutely beautiful. The similiarities to New York are apparent and well done. Especially the skyline, you at first expect it to be high tech, but as you get close to it, you can see more Eastern design influences. The entire Western, yet Eastern setting works very well with Avatar series' own mixed artwork and storytelling style, though I often find myself wondering whether standard modern clothes would look better in certain situations. But that's just me.
The machinery Steampunk/modern/World War II/Chinese design hybrid weapons, vehichles, machines and doodads are easily my most favourite thing in the series. Seriously, they are just beautiful.
The people that inhabit the current timeline of world of Avatar: I would be really hard pressed to find a character that I don't like one reason or another, including one second characters such as the Doorman in The Revelation.
I especially love the antagonists. There are great parallels between Equalists and terrorist organizations, in addition to various groups in civil wars. Tarrlok was great due to his backstory and charisma. Tahno was also pretty good due to his exceptionally wacky facial expressions(even by the Avatar standarads) and unfittingly yet fittingly manly voice.
Tenzin's family and Sato family also exceeded my expectations greatly. I sort of have a love and hate relationship with considerably more little child characters, and I wasn't expecting Asami to be this much supportive to the Krew or at least not in this way, but Pema and Airbender children were really hilarious, and Sato family's role in the story was very well done.
Mako and Bolin were also pretty great. Mako didn't interest me much initially due to his design and I didn't hear much good things about Bolin's treatment in the later episodes, but both were really enjoyable. I especially like how Bolin's Superman hair curl looks like an earthquake crack and Mako's hair looks like a flame with his eyebrows being more like stylized lightningbolts.
I don't believe Lin needs any further explanation. Her existance pretty much validates everything.
The soundtrack Much like the setting itself, it works well. Especially the radio songs which give a neat old timey America feel.
The animation As usual for short seasoned series, it is gorgeous. But I have my problems here and there. Now to the meh:
The over use of shmups(cartoony facial expressions) Avatar is known for it's expressive characters(including the random mooks), and Legend of Korra is no exception. However, to me some shmups don't have much good timing and seem to be in every once or twice a minute. While this increases the comedy relief of the series(something creators did intend to convey) with more older characters and considerably more adult storyline. On the other hand, some are timed really, really well, for example Pema's reaction when she leaves the kitchen for Mako and Asami or when Korra reacts Ikki talks about her attraction to Mako to Asami. So overall while I find some to be not so necessary, there are quite a lot that works. But still it's not enough for me to give 5 stars or anything. Four and a half maybe.
Makorra At first I found fandom's comments about this realtionship to be yet another quirk of the fandom, as after all Avatar franchise has the craziest shipping fanbase ever conceived by mankind. I was wrong. While the relationship between two is very well done storywise and they form a very effective duo against most odds, I am surprised to say this, but their chemistry just doesn't do enough for me. It doesn't insult my intelligence or his horribly conceived or anything, it's well thought out, and the most understandable outcome. Thus it doesn't annoy me. But it doesn't entertain me either. So really, I have not much to say about it. It's not bad, but it hasn't been good enough for me to praise it either. What has been exceeded my expectations is how the love triangle/square(or is it more like a hexagon without a bottom) is handled very maturely by the Krew. That's not something you will see often, or period.
Ending Just like most people, I do agree the ending felt rather rushed(well, final five minutes or so, rest is perfect), however, I have no major qualms as this mini-series was intended to be this long originally after all, and creator staff obciously have story ideas for next season. I love the actual ending credits though P :.
Lieutenant's threat level decrease This was something I expected to be raging against, but I am not mad at this too much, as most of the time he was either massively overpowered or was struck down by very quick sucker punches, so most of his failure's didn't feel dissapointing. But of course he could have been handled better.
Not enough crime syndicates being shown They couldn't even have or should not even have a major role at this season, but I really hope we will see these crazy Chinese clothing/1920s gangster mishmash clothes wearing multinational or mononational gangs later on.
Metalbending officers and White Lotus Members being not too competent It always bugs me to see law enforcers being relatively incompetent besides their chiefs or elite soldiers, and Avatar is no exception. It bugged me in the previous series, it bugs me now. It is incredibly fun to see most of the mooks, including Equalist ones, talk and showcase personality outside of their duties. And it was nice to see the seemingly corrupt officers try and help day being saved.
Naga's lower body I am pretty sure it's biologically possible but the contrast between her upper part and lower part is just too distracting.
Zuko's VA voicing General Iroh It's really, really distracting and kinda hilarious. I can't just listen to him without going wtflol, even though the character is fantastic and Dante Basco is a great VA.
Playtpus Bear's new design Given that it is an old lady's pet, it is not hard to assume that it is from a family line that has been captively bred for a few generations, as such has started to showcase more mutations and gain a more tame looking outlook. But still, old design was jus so badass.